Pouring Concrete Footings for Decks

Pouring Concrete Footings for Decks: Essential Requirements

Deck footings must be below the frost line to prevent frost heave. Use a "bell shape" at the bottom to prevent frost heave from lifting the deck. Understanding these requirements prevents deck failure.

Below Frost Line

Footings must be below frost line:

• Prevents heave: Frost won't lift footings below frost line
• Depth varies: Frost line depth varies by location
• Check local code: Local building codes specify depth
• Critical: Footings above frost line will heave

The Bell Shape

Bell shape prevents heave:

What It Is

• Wider bottom: Footing wider at bottom
• Tapered shape: Creates bell or cone shape
• Mechanical lock: Locks footing in place

Why It Works

• Resists upward force: Wider bottom resists lifting
• Mechanical advantage: Creates mechanical lock in soil
• Prevents heave: Frost can't lift bell-shaped footing
• Standard practice: Industry standard for deck footings

How to Create Bell Shape

1. Dig hole: Dig hole wider at bottom
2. Or use form: Use bell-bottom form
3. Pour concrete: Pour concrete into bell shape
4. Creates lock: Wider bottom locks in soil

The Bottom Line

Deck footings must be below the frost line and use a bell shape at the bottom. Below frost line prevents frost from reaching footing, and bell shape prevents frost heave from lifting the deck by creating a mechanical lock. Always check local codes for frost line depth and use bell-shaped footings for decks.

Need help with deck footings? Contact Local Concrete Contractor. We pour deck footings correctly with proper depth and bell shapes to prevent frost heave.